Stability Analysis On High Pier Of Railway Bridge During Construction Phase

In the recent years, with the rapid development of economy and the progress of science & technology, the construction of the railway bridge is changing fast. Because of its advantages,the high pier and long-span bridge has been widely used. Due to complex topography of China, at the same time in order to save materials and reduce the weight, Many of the high piers are often designed into hollow flexible piers. At present, more than hundred meters high bridge pier s are more and more and Its span is also getting longer and longer. Because of construction factors,stability of high pier and long span bridge becomes very important. There are many accidents originated from instability at home and abroad. This problem has become increasingly prominent, it is very meaningful to do some research and analysis on the stability of bridge with high pier and long span.Based on a super major bridge, its main span is 64+2×104+64. In this paper, I will focus on the stability of the bridge with high pier and in the process of cantilever construction.The main contents are as follows:(1) linear elastic stability analysis of high pier. First of all, to be completed 8# high pier but upper beam is not built as the research object, three dimensional model of pier is respectively established by selecting solid45 entity element and solid65 entity element with finite element software ANSYS; stability of high pier is analyzed when the pier bottom and pier top with solid segments, and the pier bottom and pier top are not including solid section and only the bottom of the pier containing solid segment. Secondly, taking the largest cantilever structure of 8# high pier as research object,and 3D model is established respectively with the solid45 element and solid65 element with steel bar, in order to analyze the stability of the pier with different thickness or different cross section hollow rate. Thirdly,the maximum cantilever structure of 8# high pier is regarded as an object of study, Then with reinforced Solid65 element to establish three-dimensional model, to find out the relationship between stability of high pier and strength of concrete.(2) High pier stability study considering the nonlinear factors at the most unfavorable cantilever construction stage. In actual construction process, in terms of construction loads, there are loads such as unbalanced weight, which is caused by the same beam segment weight difference and unbalanced load generated during construction and wind load on the high pier, the impact load when hanging basket fell. Here, there are four kinds of loading ways. To analyze stability of the high pier involving geometric nonlinear and double nonlinear at the most unfavorable cantilever construction stage.The results show that the linear elastic stability analysis method is more feasible by establishing finite element model with solid65 element with reinforced bars. Furthermore, by analyzing nonlinear stability of the high pier at the most disadvantageous cantilever phase, we find material nonlinearity influence on stability of the high pier is larger than geometric nonlinear. Therefore, it is dual nonlinear analysis that we have to consider when making stability analysis during the longest cantilever construction stage.